What are ultrasound scans?
Ultrasound scans use sound waves to build a picture of the baby in the womb. They're used to:
- check the size of your baby (this gives us a better idea of how many weeks pregnant you are and when your due date will be)
- check if you're having more than one baby
- detect some abnormalities
- look at the position of your baby and the placenta
- check that your baby is growing normally.
An appointment to have an ultrasound scan will usually take about 20 to 30 minutes.
How many will I have?
You'll be offered at least two scans: one when you're eight to 14 weeks pregnant, and one when you're between 18 and 21 weeks pregnant.
At the first scan, the sonographer will measure your baby and use the measurements to estimate your due date. At this appointment, you'll also be have screening tests for Down's, Edwards' and Patau's syndromes if you've chosen to have these tests.
At the second scan, the sonographer will look closely at your baby to check if they have some physical abnormalities.
Can I have more than two scans?
You will be offered more than two scans if your medical team feel there is a clinical reason.
You may feel that you'd like to have additional scans to share the experience of seeing your baby with family members, or for your personal reassurance. If so, you can arrange this as a private patient.
To read more about ultrasound scans in pregnancy, visit our maternity patient information page.
The NHS website also has some useful information on scans: